Liriodendron

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(Redirected from Tuliptree)

{{Taxobox | color = lightgreen | name = Liriodendron | image = Liriodendronflower0117.JPG | image_width = 240px | image_caption = Liriodendron tulipifera flower,
Sumter, South Carolina | regnum = Plantae | divisio = Magnoliophyta | classis = Magnoliopsida | ordo = Magnoliales | familia = Magnoliaceae | genus = Liriodendron | subdivision_ranks = Species | subdivision = Liriodendron chinense (Hemsl.) Sarg.
Liriodendron tulipifera L. }}

Liriodendron is a genus in the magnolia family (Magnoliaceae) consisting of two species of large deciduous trees, one native to eastern North America, the other to China and Vietnam. The standard English name is variously given as two words (tulip tree, the most common form in popular usage), hyphenated (tulip-tree), or compound (tuliptree, the most common form in botanical usage).

They are easily recognized by their leaves, which are very unusual, having four lobes in most cases and a cross-cut notched or straight apex; size varies from 8-22 cm long and 6-25 cm broad, averaging slightly larger in L. chinense but with considerable overlap between the species; the petiole is 4-18 cm long. Leaves on young trees tend to be more deeply lobed and larger size than those on mature trees (see photos, left). In autumn the leaves turn yellow, or yellow and brown.

The flowers are 3-10 cm in diameter and have nine tepals, three short outer sepal-like, and six inner petal-like, yellow-green with (L. tulipifera) or without (L. chinense) an orange patch. They are superficially similar to a tulip in shape, hence the tree's name. The stamens and pistils are arranged spirally around the spike; the stamens fall off, and the pistils become the samaras. The fruit is a cone-like aggregate of samaras 4-9 cm long, each of which has a roughly tetrahedral seed with one edge attached to the central conical spike and the other edge attached to the wing.

Like many "Arcto-Tertiary" genera, Liriodendron became extinct in Europe due to large-scale glaciation. It is known widely as fossils in Europe and well outside its natural range in Asia and North America, showing a once circumpolar distribution.

Liriodendron chinense

Asia's surviving species is the Chinese Tulip Tree, L. chinense. This native of central and southern China grows in the provinces of Anhui, Guangxi, Jiangsu, Guizhou, Hubei, Hunan, Jiangxi, Shaanxi, Zhejiang, Sichuan and Yunnan, and also locally in northern Vietnam. It is very similar to the American species, differing in the often slightly larger and more deeply-lobed leaves, and in the shorter inner tepals in the flowers, which lack the orange pigment of L. tulipifera. The Chinese Tulip Tree reaches about 40 m tall (Flora of China). It is not as hardy as the American species, but is cultivated in England, Ireland, Belgium, the Netherlands, and Germany. In North America, it grows as far north as Boston, Massachusetts in the east, and Vancouver, Canada in the west. In cultivation it grows as fast as the American Tulip Tree.

Liriodendron tulipifera

Much more widely known than L. chinense is the American Tulip Tree, L. tulipifera. It is native to eastern North America from southern Ontario and Illinois eastward across southern New England and south to central Florida and Louisiana. It can grow to more than 50 m (165 feet) in virgin cove forests of the Appalachian Mountains, often with no limbs until it reaches 25-30 m (80-100 feet) in height, making it a very valuable timber tree. It is fast-growing, without the common problems of weak wood strength and short lifespan often seen in fast-growing species. April marks the start of the flowering period in the southern USA (except as noted below); trees at the northern limit of cultivation begin to flower in June. The flowers are pale green or yellow (rarely white), with an orange band on the tepals; they yield large quantities of nectar. This species is a major honey plant in the eastern United States, yielding a dark reddish, fairly strong honey. It is also called the Tuliptree Magnolia, or sometimes confusingly, "tulip poplar" or "yellow poplar" (though it is not a poplar, family Salicaceae). The American Tulip Tree is the state tree of Indiana, Kentucky and Tennessee.

All young tulip trees and most mature specimens are intolerant of prolonged inundation; however, a coastal plain swamp ecotype in the southeastern United States (Parks et al. 1994) is relatively flood-tolerant. This ecotype is recognized by its blunt-lobed leaves, which may have a red tint. Parts of east-central Florida near Orlando have a semi-evergreen ecotype which flowers much earlier (usually in March, although flowering can begin in late January) than other types. This east central Florida ecotype seems to have the best ability to tolerate very wet conditions, where it may grow specialized root structures similar to cypress knees.

Leaf on mature tree, Sumter, South Carolina	Fall color of L. tulipifera	Seed aggregate and individual seed of L. tulipifera	Mature L. tulipifera tree
Bark of L. tulipifera.	Trunk of L. tulipifera with burls

1 Cultivation and uses
2 Cultivars of L. tulipifera
3 See also
4 References and external links

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Cultivation and uses

Tulip trees make magnificently-shaped specimen trees, but are very large, growing to about 35 m in good soil. They grow best in deep well-drained loam which has thick dark topsoil. They show stronger response to fertilizer compounds (those with low salt index are preferred) than most other trees, but soil structure and organic matter content are more important. The southeastern coastal plain and east central Florida ecotypes occur in wet but not stagnant soils which are high in organic matter. All tulip trees are unreliable in clay flats which are subject to ponding and flooding. Like other members of the Magnolia family, they have fleshy roots that are easily broken if handled roughly. Transplanting should be done in early spring, before leaf-out; this timing is especially important in the more northern areas. Fall planting is often successful in Florida. The east central Florida ecotype may be more easily moved than other strains because its roots grow over nine or ten months every year -- several months longer than other ecotypes. Most tulip trees have low tolerance of drought, although Florida natives (especially the east central ecotype) fare better than southeastern coastal plain or northern inland specimens.

Juvenile foliage of L. tulipifera, east central Florida ecotype. Note the blunt lobes and red petioles. Photo by William Moriaty.

More mature foliage of L. tulipifera, east central Florida ecotype. Photo by William Moriaty.

Another view of foliage from east central Florida Liriodendron. Photo by William Moriaty.

Mature east central Florida L. tulipifera, Dr. Howard A. Kelly Park near Apopka, Florida. Photo by William Moriaty.

L. tulipifera has been introduced to many temperate parts of the world, at least as far north as Oslo, Norway. In the Southern Hemisphere, it is cultivated in parts of Argentina, Australia, Chile, New Zealand, South Africa, and Uruguay. In Canada, it is native to that part of Ontario south of a line from Hamilton to Sarnia, with many specimens in Rondeau Provincial Park, but most cultivation is seen in British Columbia. There, it has been planted on the Queen Charlotte Islands, and in the southern interior as far north as Vernon. Its easternmost cultivation is at Creston. It is common in southwestern cities such as Burnaby, New Westminster, Port Alberni, Vancouver and Victoria. In the United States, introductions have been most successful in parts of Washington, Oregon, California, Oklahoma and Texas. A few are in Idaho, Nevada, Utah, Colorado, Nebraska, Kansas, Iowa, Minnesota, Wisconsin, New Hampshire and Maine. The east central Florida ecotype grows well in Palm Beach County, Florida and Austin, Texas.

The soft, fine-grained wood of tulip trees is misleadingly known as "poplar" (short for "yellow poplar") in the U.S., but marketed abroad as "American tulipwood" or by other names. It is very widely used where a cheap, easy-to-work and stable wood is needed, but not a strong or a good-looking wood. It is clearly the wood of choice for use in organs, due to its ability to take a fine, smooth, precisely-cut finish and so to effectively seal against pipes and valves. It is also commonly used for siding clapboards. Its wood may be compared in texture, strength, and softness to white pine.

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Cultivars of L. tulipifera

'Ardis' - shorter, with smaller leaves than wild form.
'Arnold' - narrow, columnar crown; may flower at early age.
'Aureomarginatum' - variegated form with pale-edged leaves; sold as 'Flashlight' or 'Majestic Beauty'.
'Fastigatum' - similar form to 'Arnold'.
'Florida Strain' - blunt-lobed leaves, fast grower, flowers at early age.
'Integrifolium' - leaves without lower lobes.
'Mediopictum' - variegated form with yellow spot near center of leaf.
'Roothaan' - blunt-lobed leaves.

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